Hydraulic pump for propeller pitch changing mechanisms



J. E. ANDERSON 2,494,606 HYDRAULIC PUMP FOR PROPELLER PITCH CHANGING MECHANISMS Original Filed A ril s, 1943 .Fan. 17, 1950 3 Sheets-Sheet l INVENTOR JabnEfiuim'aazz WW 4. W

ATTORNE Jan. 17, 1950 J. E. ANDERSON 2,494,606

' HYDRAULIC PUMP FOR PROPELLER PITCH CHANGING MECHANISMS Original Filed April 8, 1943 3 Sheets-Sheet 2 Jan. 17,1950

J. E. ANDERSON HYDRAULIC PUMP FOR PROPELLER PITCH CHANGING MECHANISMS Original Filed April 8, 1943 3 Sheets-Sheet 3 /4@ K95 /56 a M M I Ira. 1193130? John 7460 as d/W 5 sou fliiorawqq Patented Jan. 17, 1950 HYDRAULIC PUMP FOR PROPELLER PITCH CHANGING MECHANISMS John E. Anderson, Portland, Conn., assignor to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Original application April s, 1943, Serial No.

482,264. Divided and this application September 21, 1944, Serial No. 555,111

8 Claims.

This application is a division of United States application Serial No. 482,264, filed April 8, 1943, by John E. Anderson, for Pumps for hydraulic pitch changing mechanisms, which matured into Patent No. 2,462,931 on March 1, 1949.

An object of this invention is to provide a pump construction and arrangement especially adapted for use on hydraulically controlled aircraft propellets.

The invention comprises a multi-cylinder pump having cylinders and pistons circumferentially arranged around a common center, and operated by suitable means such as the engine driving the propeller.

The cylinders are supported in an annular supply manifold or sump rotatable with the propeller hub.

Each cylinder has a radially movable piston, all pistons being reciprocated by a central cam.

Another object of the invention is the provision of improved means for unfeathering the propeller when the engineis not operating.

The individual pumps discharge into an annular manifold which, for convenience, may be supported within the supply manifold.

Other objects and advantages will be apparent from the specification and claims and from the accompanying drawing which illustrates what is now considered to be a preferred form of the invention;

In the drawing, Fig. l is largely a diagrammatic cross section of the pump in a plane perpendicular to the axis in rotation, and

Fig. 2 is a reduced scale of a diagrammatic side view of the invention installed on an aircraft.

Fig. 3 is a longitudinal sectional view of the pumps and associated mechanism assembled on a propeller.

Fig. 4 is a schematic view partially in section showing the propeller pitch changing mechanism, the sump, the control valve and the connections therebetween.

The cylindrical pump actuating member it is rotatably mounted by means of roller bearings on the rear end it of the propeller hub it. The propeller it and hub it are driven from the engine 65 by the drive shaft i2.

Gear teeth 93 on member iii engage gear iii which is prevented from being rotated in one direction only by the engine by latch H which engages with the teeth of gear it. Thus, when the engine is rotating the propeller and hub, pump operating member ID is stationary.

The member it is.provided with an eccentric cam in the form of flange ii. The propeller hub 14 rotates with propeller l6 and supports the six individual pump units I8 and the reservoir manifold 20 from which the units draw their supply of oil.

Each piston 22 has a roller 24 hearing on the sage 3A in pump body I8, oil will flow from sump 20 through passage 34 into high pressure cylinder 36, and on the out stroke the oil will be forced through passage 38 and check valve 40 into discharge manifold 42 from which it will pass through passage 66 to the control valves of the propeller.

A safety valve it, discharging into sump 20, maintains a. comparatively high pressure in manifold 62, for instance 3,000 pounds per square inch.

The large diameter part 30 of each pump pis-= ton serves to scavenge the lubricating oil and all leakage that may collect within the pump trough 55, drawing the oil through inlet 46 and forcing it into sump 20 past check valve 50. This pump has capacity enough to pump air if necessary.

The pressure in sump 20 may be relieved through safety valve 52 at comparatively low pressure, for instance twenty-five pounds per square inch.

Lubricating oil which is under pressure from the propeller hub returns to sump it through check valve 56, which may be set at about thirtyfive pounds per square inch.

Only one pump unit has been described, but it will be understood that the other units work in similar manner all drawing oil from sump 2t! and discharging through manifold 32.

Thus, it will be seen that when the engine is driving the propellenthe pumps it will rotate about the stationary eccentric 25 to provide high pressure oil through passage Mi for feathering and unfeathering the propeller.

The propeller comprises a hub it having an internally splined bore into which the externally splined end of the propeller shaft i2 is fitted. The hub is secured on shaft i2, adjacent the engine by conical rings 56 and 58 and nut "it, in a well known manner. The blades are retained in their sockets by thrust bearings comprising circular grooves filled with steel balls I2, the balls being inserted through holes I4 in the wall of the sockets while the blades are in loading position with the end of vane motor I8 against hub I4, after which the holes are closed by plugs I6 and the blades are moved outwardly to their operative positions.

The pitch changing vane motor I8 is located within the shank of each blade, and is particularly illustrated and described in United States application Serial No. 474,638 filed February 4, 1943, by John E. Anderson and Arthur N. Allen, Jr., for Propellers. The three vane motors for a. three bladed propeller are schematically shown at 18a, 18b and 180 in Fig. 4.

- Each motor has fluid conduits, as indicated at 8082, 84-86, and 8890 (Fig. 4). Each conduit is, in reality, also connected by passages, not shown, to the chamber diametrically opposite the chamber to which it is shown to be connected in the drawing. Each motor comprises a fixed inner member 98 having a pair of abutments 99, and an outer member I having a pair of vanes IOI and rotatable about inner member 98 to change the pitch of the blades. The fluid connections to the motors lead from manifolds I02 and I04 (Figs. 3 and 4) extending around the propeller hub, and these'manifolds are connected with the control valve generally indicated at I06, by channels I08 and H0. The passages 92, 94 and 96 take care of leakage from the vane motors.

The blades are interconnected for simultaneous and coextensive movements by a three piece adjustable bevel gear 2 (Fig. 3), rotatably supported on a bearing II3 mounted in hub I4coaxial with shaft I2 and meshing with gear sectors secured to the shank ends of the blades, the sector for blade I6 being indicated at I I4 (Fig. 3) Limiting positions of the propeller blades in their pitch changing movements are determined by stop rings II 6 and H8 (Fig. 3) cooperating with a member rotatable with gear I I2.

Fluid for operating the motors is supplied by a pump generally indicated at I 8. Valve I06 (Figs. 3 and 4) comprises three concentric members, the fixed outer bushing I40, the slidable intermediate follow-up sleeve valve I42 and the slidable inner control valve I 44. Bushing I00 is fixed in the propeller hub parallel to the axis of shaft I2.

Follow-up valve I42 is in the form of a sleeve provided with end lands I46 and I48 and inter mediate lands I50 and I52, the adjacent lands being separated by annular spaces in the sleeve, which overlie ports I54, I56 and I58 in bushing I40, connecting with the above annular spaces. Follow-up valve I42 is provided with ports I60, I62 and I64 leading from the interior to the exterior thereof, and control valv I44 is provided with spaced lands I66 and I68 which serve to control ports I60 and I64 in a manner to be presently described.

Sleeve valve I42 is moved in accordance with the pitch changing movements of the propeller blade through connection with blade synchronizing gear H2. To gear H2 is secured a spur gear I61 which, through an idler pinion I12, drives pinion I14 formed at one end of sleeve I85 (Figs. 3 and 4) in which are two helical cam grooves I83, 180 degrees apart. Sleeve I85 rotates around an inner sleeve I89 which is provided with diametrically opposed longitudinal slots I8I (Figs. 3 and 4). A pin I86, through the end of valve I42 passes through slots I81 with each end of the pin in one of the cam grooves I83. Sleeve I89 and its slots I8! are nonrotatable with respect to the hub, being integral with cap I9I which is secured to the hub by screws I93. With the above structure in mind, it will be realized that rotation of gear II4 will rotatecam I85. Cam grooves I83 engage the ends of pin I86 and therefore move the pin longitudinally along slots I81, and the pin will move valve I42 with it. Thus is estab lished the control of follow-up valve I42 from gear II2, through gear I14 and pin I 36.

Control valve I44 is connected through a screw threaded rod I90 with a ring I92 which is connected to an axially movable but nonrotatable member I94 by a flat slip ring I96 engaging aligned grooves in ring I92 and member I 94. A pin I95 (Fig. 2) extending through a longitudinal slot I91 in control valve I44, and secured at its ends in follow-up sleeve I42 limits the extent of longitudinal movement of valve I44 relative to the sleeve. Pin I95 is also used for adjusting the position of the control valve through threaded rod I 90. The pin is kept from rotating by engaging holes in follow-up sleeve I42, which in turn is prevented from rotating by pin I86 in slots I8'I. To adjust the position of the control valve screws I93 are removed, sleeve I89 is rotated a proper amount, and screws I 93 are replaced.

Member I94 is movable by a pitch control mechanism, not illustrated, but which may be of the character illustrated and described in United States application Serial No. 422,252, filed December 9, 1941, by Perin and Richmond, for Propeller control means, (now abandoned in favor of continuation application Serial No. 17,644, filed February 21, 1949), and assigned to the assignee of this application. In such an arrangement a servo-motor operated rack I98 imparts a slight rotational movement to member I94 to cause a relative movement between external spiral splines I9'I' provided on member I94 and corresponding internal spiral splines I99 in an annular member 200 rigidly secured, by annular bracket 202, to the front'end of the casing of engine 65.

Because of the spiral arrangement of splines I91 and I99 the slight rotational movement of member I94 will cause a longitudinal movement of this member proportional to the movement of straight-toothed rack I98 which engages teeth 204 provided on a portion of member I94. For the number of straight teeth in I94 plus the necessary rotational travel, the spiral teeth in fixed member 200 are removed. Movement of rack I98 may also be utilized to turn the rotor of a generator 206 of a Selsyn pitch indicating apparatus.

The pump pressure manifold 42 is connected (Figs. 1, 3 and 4) through pipe 44 and plug 2) (Fig. 2) with port I56 in tube I40, while channel I08 leading to manifold I02 is connected with port I54, and channel IIO leading to manifold I04 is connected with port I58. With this arrangement, fluid under pressure from the pump is supplied through port I56 in tube I40 and port I62 in follow-up valve I 42 to the annular space within the valve between lands 66 and I68 of control valve I44. Flow of fluid from this space to either manifold I02 or I04 is controlled by movement of control valve I44. When that valve is moved to the left as viewed in Figs. 3 and 4, fluid will flow from the space within valve I42 between lands I66 and I68 of valve I44 through port I60 in valve I42, and port I54 in tube I40, and thence through channel I08 to manifold I02 to supply hydraulic fluid to one side of each pitch changing motor. At the same time, exhaust fluid from the opposite sides of the motors will flow interior of the propeller hub.

When valve I44 is moved to the right as viewed in Figs. 3 and 4, fluid will be supplied from 2H1 through ports I56, I62, I64, I58 and channel IIB to manifold I04, while the exhaust fluid from the opposite side of the motors will flow from manifold I02 through channels I08 and I54, through ports I60 and .holes 2I2, into valve I44, and thus through the front end of sleeve I42 into the propeller hub, as described above.

When valve I44 has been moved a certain distance corresponding to a speed change demand of the governor control apparatus, one side of each motor will be connected with the fluid from the pump pressure manifold 42 in the manner described above and the opposite sides of the motors will be vented to the sump '20. The rotatable portions of the motors will thereupon start to rotate turning the propeller blades to change the propeller pitch. As the blades are rotated gear H2 is also rotated, and it rotates member I85 causing pin I86 to track through cam slot I83 thereby moving follow-up valve I42 in the same direction in which the control valve I44 was moved. When the blades have changed their pitch an amount corresponding to the movement of valve I 44, sleeve I42 will have reached a position in which ports I60 and I64 are again centered relative to lands I66 and I68 of control valve I44 and movement of the motors will thereupon cease. When valve I42 is in the above position relative to plunger I44, lands I66 and I68 have negative lap i. e., they fail to entirely cover ports I64 and I64 but provide bleeder openings through 'the ports and surplus output of the pump can flow through control valve I42 to drain. Thus the valves act to unload the pump when the pitch changing motors are not operating and also maintains an equal pressure on both sides of the pitch changing motors. As soon, however, as control valve I44 moves with respect to follow-up valve I42 negative lap will be eliminated and the output of the motor will be directed to one side or the other of the pitch changing motors, depending upon the direction of movement of valve 544, and the opposit sides of the motors will be connected with drain in the manner described above. The position of valve I44 may be adjusted relative to ring I92 by the adjustable screw thread connection 234 to obtain the proper position of this valve relative to follow-up valve I42.

High pressure and low pressure relief valves 4%, 54 respectively are included in the pitch changing hydraulic system to supplement the operation of control valve M36. The high pressure relief or blow-oif valve 46 is provided to vent the pump outlet at a predetermined safe maximum pressure in the event the control valve I66 should, for some reason, fail to entirely dispose of the pump output. The low pressure controlv or exhaust pressure valve, interposed between the space within the propeller hub and the sump 2G is provided mainly to insure that the hub remains full of fluid for lubricating purposes. The space within the hub which hydraulically connects valves I66 and 54 is diagrammatically indicated by the channel 240 in Fig. 4.

It is also desired to provide means for unfeathering the propeller in the event the engine is inoperative. This is accomplished by means of electric motor 60 which is mounted on bracket 62 fixed to the engine nose. The motor 60 may be energized to rotate pump actuating member I 0 through worm drive 64 and gears I5 and I3,

and hence cause eccentric 2| to rotate relatively to the now stationary pumps I8 and provide high pressure oil for unfeathering the propeller. The

number of pumps, the location of their inlets, and

the quantity of oil in the sump are selected to insure a supply of oil to at least one of the pumps in every stationary position of the propeller.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

I claim:

1. A device for feathering airplane propellers comprising in combination, a cam, an annular manifold surrounding said cam, pump units supported by said manifold and surrounding and in operative engagement with said cam, a propeller including pitch control mechanism, a propeller drive shaft, said manifold, pumps, and propeller being rotated about said cam by said drive shaft to operate said pump, and means for rotating said cam and operating said pump to withdraw fluid from said manifold and deliver fluid to said propeller pitch control mechanism when said drive shaft is stationary.

2. In combination with an airplane propeller having hydraulically actuated pitch changing means including means for feathering said propeller, pump means carried by and rotatable with said propeller for supplying hydraulic fluid under pressure to said pitch changing means, a substantially constant volume sump for storing hydraulic fluid also carried by and rotatable with said propeller, a plurality of pump inlets connected with said pump means, said inlets including a plurality of inlet openings in said sump said inlet openings being spaced around said sump so as to be submerged in fluid held against the outer walls of said sump by centrifugal force when said propeller is rotating and spaced so that at least one of said inlet openings is always submerged in fluid held against a wall of said sump by gravity when the propeller is not rotating, and means for actuating said pump means both when the propeller is rotating and when the propeller is not rotating. I

3. In combination with an airplane propeller, having hydraulically actuated pitch changing means including means for unfeathering said propeller, pump means carried by and rotatable with said propeller for supplying liquid under pressure to said pitch changing means, a substantially constant volume sump for storing liquid also carried by and rotatable with said propeller, a plurality of pump inlets connected with said pump means, said inlets including a plurality of inlet openings in said sump, said inlet openings being spaced around said sump so as to be submerged in liquid held against the outer walls of said sump by centrifugal force when said propeller is rotating, and spaced so that at least one of said inlet openings is always submerged in liquid held against a wall of said sump by gravity when the propeller is not rotating and means for actuating said pump means when the propeller is not rotating to pump liquid from said sump, through an opening submerged when the propeller is not rotating, to said pitch changing means to unfeather the propeller.

4. In combination with an airplane propeller mounted on a propeller drive shaft, and having hydraulically actuated pitch changing means ineluding means for imfeathering said propeller, pump means carried by and rotatable with said propeller for supplying liquid under pressure to said pitch changing means, an annular substantially constant volume sump carried by and rotatable with said propeller and substantially concentric with said drive shaft for storing liquid, a plurality of pump inlets connected with said pump means, said inlets including a plurality of inlet openings in said sump, said inl t openings being substantially equally spaced around the periphery of the interior of said sump so as to be submerged in liquid held against said periphery by centrifugal force when said propeller is rotating, and spaced so that at least one of said inlet openings is always submerged in liquid held against said periphery by gravity when the propeller is not rotating, and means for actuating said pump means both when the propeller is rotating and when the propeller is not rotating,

5. A device for unieathering non-rotating airplane propellers comprising in combination, a propeller including pitch control mechanism, a propeller drive shaft, a sump carried by said propeller, a plurality of pump units for supplying unfeathering fluid to said propeller stitch control mechanism arranged around said drive shaft and carried by and operatively connected with said sump, each pump unit comprising one part rotatable with said propeller and another part 7. A device for unieatherlng airplane propellers comprising in combination, a propeller, a propeller drive shaft, an annular substantially constant volume sump secured to and rotatable with said propeller for storing a, supply of pitch changing fluid, a plurality of pumps carried by said sump and rotatable therewith, each pump having an individual intake submerged in said fluid when said propeller is rotating at least one of which pumps will have its intake submerged in said fluid when the propeller is not rotating, and means for operating said pumps both when the propeller is rotating and when it is not rotating.

8. A device for unieathering a non-rotating airplane propeller having hydraulically actuated pitch changing mechanism carried by said-proheld against rotation said pump being operated to pump fluid by relative rotation of said parts and means for rotating said other part and supplying unieathering fluid to said propeller pitch control mechanism from said sump when said propeller is not rotating.

6. A device for unfeathering non-rotating airplane propellers comprising in combination, a propeller including pitch control mechanism, a propeller drive shaft, an annular sump substantially concentric with and arranged around said drive shaft, a plurality of pump units located in and connected with said sump and substantially equally spaced around said drive shaft each pump unit comprising one part connected with said sump for rotation therewith and another part held against rotation, said pump being operated to pump fluid by relative rotation of said parts, and means for rotating said other part and supplying unfeathering fluid to said propeller pitch control mechanism from said sump when said propeller is not rotating.

peller, comprising in combination, a substantially constant volume sump carried by said propeller for storing a supply of pitch changing liquid, a plurality of pump units carried by said propeller adjacent said sump, each pump unit having a separate individual inlet in said sump adjacent the respective pump, traveling through an orbit by rotation of said propeller, and located near the bottom of said sump when said respective inlet is at the bottom of its orbit, and means for operating said pump units when the propeller is not rotating to pump liquid through the inlet located near the bottom of said sump to said pitch changing mechanism to unfeather said propeller. J OHN E. ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date Great Britain Feb. 25,1938 Germany Aug. 30, 1934 Number Number 

